At any airport, particularly in the instance of commercial aviation, incoming aircraft are normally refueled and prepared for further use, directly at a loading gate. This procedure facilitates effective usage of the aircraft and avoids moving it to a loading areas solely for the purpose of one flight preparation.
Since the principal pre-flight preparation involves refueling, the following disclosure will be addressed solely to this subject.
Although tanker trucks carrying aviation fuel are often used for the refueling operation, such trucks are normally cumbersome. They can constitute a traffic problem as well as a physical hazard and may be incapable of carrying sufficient quantities of fuel. These undesirable conditions are found to be true in any loading area where varied types of vehicles and personnel are moving about toward preparing an aircraft for flight.
To avoid the use of moving tanker trucks for this diverse operation it has been found desirable to utilize an underground fuel system. Such a system connects with a main fuel source, having valve outlets at each terminal gate, or positioned where an aircraft can be conveniently refueled.
As a matter of practicality, in this form of fuel transfer system, the valve at each terminal is usually embedded into the ground and furnished with a cover to avoid being a hazard to equipment and personnel. Thus, the flow control valve, often referred to as a pit valve, is placed within a casing or similar enclosure means which is embedded into the substrate beneath ground level.
To be manually accessible for a refueling operation, the control valve is close enough to ground level that it can be readily provisionally connected to a fuel transfer conductor. When the latter is utilized, the conductor hose is brought to the aircraft by a refueling crew. The conductor will normally be comprised of a coupling at one end which detachably engages the discharge port of the pit valve. The other end of the conductor will comprise a nozzle adapted to engage, the aircraft fuel tank.
Operationally, when the necessary connection is made between a pit valve and the aircraft, opening of the valve will initiate a flow of fuel from the underground source, through the pit valve and into the aircraft tank.
An ever present defect in this type of system results from the fuel transfer conductor and its connection to the underground control valve, being inconspicuous during the refueling operation. Experience has shown that in view of the number of vehicles which move about the aircraft, the fuel conductor connection is in constant jeopardy. The degree of the peril increases substantially at night when the fuel conducting hose may not be as visible as it should be.
It can be appreciated that a vehicle such as a luggage carrier, a food loading truck or the like, could inadvertently come into rolling contact with the fuel carrying hose or the coupling which is engaged to the pit valve.
In such an instance, the hose, as well as the pit valve connection will be placed in danger of being damaged or broken. The result could be severed hose or distorted control valve and coupling connection, with fuel being discharged under pressure about the immediate area.
Toward precluding or minimizing the possibilities of fuel being inadvertently discharged during the aircraft refueling operation, there is here disclosed a protective apparatus that can be applied at ground level. Functionally, it forms a protective barrier to the subsurface control valve and, the detachable coupling, as well as to a portion of the fuel carrying hose itself.
The protective unit is provisionally placed across the pit valve casing to form a rigid, rotatable partial closure to the casing open upper end. The protective member further includes an appendage which registers about a short section of the fuel carrying hose immediately adjacent to the control valve.
The fuel conductor includes a coupling having a lifting handle or bail which facilitates the conductor being manipulated into place for sealably engaging a valve discharge port. With the protective unit in place, the coupling, as well as the valve and the conductor hose will be afforced a degree of protection in the event a truck or similar wheeled vehicle inadvertently contacts or rolls over the protecting element.
It is therefore an object of the invention to provide protective enclosure to a pit valve installation which is connected to a source of fuel, and which discharges said fuel through a conductor in the course of the fuel being transferred to an aircraft fuel tank.